Category Archives: Genetic Engineering

Hematoxylin and eosin (H&E) staining of sections of wild-type (top row) and H1 triple-knockout (bottom row) embryoid bodies. After 14 days in rotary suspension culture, the wild-type embryoid bodies showed more differentiated morphologies with cysts forming (black arrows) and the knockout embryoid bodies failed to form cavities (far right). (Credit: Yuhong Fan)

(Phys.org) -- New research findings show that embryonic stem cells unable to fully compact the DNA inside them cannot complete their primary task: differentiation into specific cell types that give rise to the various types of tissues and structures in the body.

Researchers from the Georgia Institute of Technology and Emory University found that chromatin compaction is required for proper embryonic stem cell differentiation to occur. Chromatin, which is composed of histone proteins and DNA, packages DNA into a smaller volume so that it fits inside a cell.

A study published on May 10, 2012 in the journal PLoS Genetics found that embryonic stem cells lacking several histone H1 subtypes and exhibiting reduced chromatin compaction suffered from impaired differentiation under multiple scenarios and demonstrated inefficiency in silencing genes that must be suppressed to induce differentiation.

While researchers have observed that embryonic stem cells exhibit a relaxed, open chromatin structure and differentiated cells exhibit a compact chromatin structure, our study is the first to show that this compaction is not a mere consequence of the differentiation process but is instead a necessity for differentiation to proceed normally, said Yuhong Fan, an assistant professor in the Georgia Tech School of Biology.

Fan and Todd McDevitt, an associate professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, led the study with assistance from Georgia Tech graduate students Yunzhe Zhang and Kaixiang Cao, research technician Marissa Cooke, and postdoctoral fellow Shiraj Panjwani.

The work was supported by the National Institutes of Healths National Institute of General Medical Sciences (NIGMS), the National Science Foundation, a Georgia Cancer Coalition Distinguished Scholar Award, and a Johnson & Johnson/Georgia Tech Healthcare Innovation Award.

Enlarge

Phase contrast images showing that H1 triple-knockout (bottom) embryonic stem cells were unable to adequately form neurites and neural networks compared to wild-type embryonic stem cells (top). (Click image for high-resolution version. Credit: Yuhong Fan)

Enlarge

More here:
Genetic packing: Successful stem cell differentiation requires DNA compaction, study finds

With some clever genetic engineering but without ever touching a cell or an animal, scientist can remotely control cells using ultrasound, light,and, now, also radio waves. The electromagnetic waves can be used to selectivelyheat up parts of cells and activate a gene to make insulin in mice, according to a recent study published in Science.

But why care about radio waves if we have light and ultrasound?Radio waves have a couple distinct advantages over existing techniques.

In the current study, the radio waves didnt heat up a whole patch of tissue or even a whole cellit only affected specific pores in the cell, calledTRPV1,that open in response to heat. To get this specificity, the scientists made special iron oxide nanoparticles attached to an antibody that only sticks to TRPV1. When they turned on the radio waves, the iron oxide particles warmed up and opened the TRPV1 channel, minimally affecting the rest of the cell or surrounding cells.Ultrasound, on the other hand, heats up a whole patch of tissue to 42 Celsius, which could have damaging or confounding effects on the cells.

Radio waves, unlike light, can also penetrate deep into tissue. To show how the radio could safely work inside an animal, scientists injected mice with special cells that had been genetically engineered to include both the TRPV1 pore and a gene switch that would release insulin when exposed to calcium. Then they got those cells in the mice to start making insulin with a little Rube Goldberg-esque cellular machine: heat from the radio waves opened the TRPV1 channels, calcium rushed into the cells through the open TRPV1, the flood of calcium turned on the insulin gene switch, and, finally, the cells began making insulin. (The whole chain of events makes you appreciate the complexity of biology, right?)

In one last step, the scientists did away with the synthetic iron oxide nanoparticles altogther. They got cells to produce their own iron nanoparticles, a iron storage protein calledferritin. When they tested ferritin in cells, it was 2/3 as effective at inducing insulin production as the synthetic nanoparticles.

There could be medical applications for activating genes in stem cell therapy in the future, but for now, this is just pretty cool: scientists can turn on some radio waves and hack right into the cellular machinery of a mouse.

[via Nature News]

Mouse image via Shutterstock / lculig

View post:
Now *This* Is a Cell Phone: Using Radio Waves to Control Specific Genes in Mice | 80beats

Devangshu Datta: Towards an HIV cure Advances in genetic engineering techniques may finally help us win the battle against this global scourge Devangshu Datta / New Delhi May 04, 2012, 00:53 IST

Since AIDS, or acquired immune deficiency syndrome, was identified in 1981, there has been only one medically-certified cure. That occurred under unusual circumstances and it gave researchers an important clue about new ways to attack the disease. Recent advances in genetic engineering techniques have aided in this process. Some studies offer new hope of a cure for the 35 million estimated to be infected worldwide.

No disease inspires as much superstitious dread. So far, AIDS is estimated to have killed over 30 million people and it infects millions every year. It is especially prevalent in Sub-Saharan Africa.

HIV is transmitted through the exchange of body fluids. Common causes of infection (not necessarily in order) include unprotected sex, blood transfusions, sharing needles and so on. The associations with promiscuity and drug addiction make it hard to implement policies to stop HIV-spread. What works best is a combination of sex education and drug awareness programmes, coupled with easy availability of condoms and disposable needles. But in conservative societies like India, people object to sex education. Some religions also discourage the use of condoms.

Someone infected with HIV (HIV-positive) may survive years, without symptoms. The virus attacks a class of white blood cells called CD4 T-cells. It inserts itself into the cell and replicates. T-cells are part of the natural immune system. Once AIDS develops owing to HIV taking over T-cells, the immune system shuts down. Most AIDS patients die of cancer, pneumonia, or some other infection.

The new approaches involve inserting immune genes into HIV-positive patients, through genetic engineering of stem cells. Every researcher is cautious about claims of cures. The characteristic long symptom-less periods and HIVs ability to hide can be cruelly deceptive. HIV-positive people are also vulnerable to quacks. Many charlatans, including a cross-dresser who teaches yoga on Indian television, have claimed at various times to have found AIDS cures.

Some people have natural genetic immunity for various reasons. Advances in understanding of genomes have helped identify some of the causes of immunity. Researchers have known for a while that a mutated gene called CCR5 Delta 32 offers natural immunity to HIV.

The mutation is rare and found only in a few northern Europeans. The normal CCR5 gene, which most people possess, is the receptor HIV uses to enter T-cells. HIV cannot use the Delta-32 mutated gene and, hence, cannot replicate in a host who has two copies of the CCR5 Delta 32 gene (one inherited from each parent). Even one copy of Delta 32 seems to offer some protection. Only about one per cent of northern Europeans possess both copies.

In 2007, Timothy Ray Brown, an American resident in Berlin, was HIV-positive and also under treatment for leukaemia. Leukaemia causes an abnormal increase in white blood cells and a drop in red cells. Blood cells are produced by bone marrow. One drastic treatment is a bone marrow stem cell transplant from a healthy person. This helps regenerate healthy blood with a good haemoglobin ratio, and a new immune system. Its dangerous since the patients entire immune system must be destroyed prior to the transplant.

Browns doctors at the Charite University Medicine Berlin, Kristina Allers and Gero Hutter, found a compatible donor who belonged to that rare one per cent with the Delta-32 mutation. Five years later, after the transplant procedures, the Berlin Patient, as Brown is called in medical journals, is still HIV-free and doctors concur that this is a functional cure.

Read more here:
Devangshu Datta: Towards an HIV cure

St. Louis /PRNewswire/ -- Sigma-Aldrich Corporation (Nasdaq: SIAL) today announced that Sigma Advanced Genetic Engineering (SAGE) Labs, an initiative of Sigma Life Science, extended CompoZr Zinc Finger Nuclease (ZFN) technology to achieve the first tissue-specific conditional knockout of an endogenous gene in rats. For two decades this approach for generating sophisticated disease models could be performed only in mice. Rats, however, are preferred by drug discovery and basic researchers because the animal's physiology, neurobiology and other features are more predictive of human conditions. Rats engineered to contain tissue-specific conditional gene knockouts are available exclusively through the SAGEspeed Custom Model Development Service. Details are available at http://www.sageresearchmodels.com/conditional-KO.

Conventional gene knockout eliminates a gene throughout an entire animal. In contrast, conditional gene knockout can eliminate a gene solely in the relevant tissue or organ, leading to a more accurate understanding of the gene's function. Conditional gene knockout can also knock out genes at certain points in development, enabling studies of genes whose absence in embryos is lethal, but whose loss of function in adulthood is critical to investigate for many human diseases.

"Almost 89% of drug candidates fail to achieve approval," said Edward Weinstein, Director of SAGE Labs. "Basic and drug discovery researchers need access to more predictive animal models whose physiology, biology, and genetics more closely reflect specific human conditions. SAGE Labs is applying ZFN technology to achieve previously impossible genetic manipulations, such as tissue-specific gene deletion in rats."

Using the conditional knockout methodology, scientists at SAGE Labs have generated a pair of rat lines in which two important neuronal genes, Crhr1 and Grin1, were removed in specific neuronal populations. Crhr1 and Grin1 have been implicated as playing a role in depression and schizophrenia, respectively. The rat lines were developed through the SAGEspeed model creation process, which uses Sigma's CompoZr ZFN technology to create sophisticated genetic modifications in rats, mice, rabbits, and other organisms. CompoZr ZFN technology is the first to enable highly efficient, targeted editing of the genome of any species.

For more information and to request pricing, visit http://www.sageresearchmodels.com.

Cautionary Statement: The foregoing release contains forward-looking statements that can be identified by terminology such as "enable," "enabling," "leading to," "achieve," "predictive" or similar expressions, or by expressed or implied discussions regarding potential future revenues from products derived there from. You should not place undue reliance on these statements. Such forward-looking statements reflect the current views of management regarding future events, and involve known and unknown risks, uncertainties and other factors that may cause actual results to be materially different from any future results, performance or achievements expressed or implied by such statements. There can be no guarantee that iPS cells, iPS-cell derived primary cell lines, novel assays, or related custom services will assist the Company to achieve any particular levels of revenue in the future. In particular, management's expectations regarding products associated iPS cells, iPS-cell derived primary cell lines, novel assays, or related custom services could be affected by, among other things, unexpected regulatory actions or delays or government regulation generally; the Company's ability to obtain or maintain patent or other proprietary intellectual property protection; competition in general; government, industry and general public pricing pressures; the impact that the foregoing factors could have on the values attributed to the Company's assets and liabilities as recorded in its consolidated balance sheet, and other risks and factors referred to in Sigma-Aldrich's current Form 10-K on file with the US Securities and Exchange Commission. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those anticipated, believed, estimated or expected. Sigma-Aldrich is providing the information in this press release as of this date and does not undertake any obligation to update any forward-looking statements contained in this press release as a result of new information, future events or otherwise.

About Sigma Life Science: Sigma Life Science is a Sigma-Aldrich business that represents the Company's leadership in innovative biological products and services for the global life science market and offers an array of biologically-rich products and reagents that researchers use in scientific investigation. Product areas include biomolecules, genomics and functional genomics, cells and cell-based assays, transgenics, protein assays, stem cell research, epigenetics and custom services/oligonucleotides. Sigma Life Science also provides an extensive range critical bioessentials like biochemicals, antibiotics, buffers, carbohydrates, enzymes, forensic tools, hematology and histology, nucleotides, amino acids and their derivatives, and cell culture media.

About Sigma-Aldrich: Sigma-Aldrich is a leading Life Science and High Technology company whose biochemical, organic chemical products, kits and services are used in scientific research, including genomic and proteomic research, biotechnology, pharmaceutical development, the diagnosis of disease and as key components in pharmaceutical, diagnostics and high technology manufacturing. Sigma-Aldrich customers include more than 1.3 million scientists and technologists in life science companies, university and government institutions, hospitals and industry. The Company operates in 40 countries and has nearly 9,000 employees whose objective is to provide excellent service worldwide. Sigma-Aldrich is committed to accelerating customer success through innovation and leadership in Life Science and High Technology. For more information about Sigma-Aldrich, please visit its website at http://www.sigma-aldrich.com.

Sigma-Aldrich and Sigma are trademarks of Sigma-Aldrich Co, LLC registered in the US and other countries. SAGE and CompoZr are registered trademarks of Sigma-Aldrich Co. LLC. SAGEspeed is a trademark of Sigma-Aldrich Co. LLC.

SOURCE: Sigma-Aldrich Corporation

Read the original here:
SAGE® Labs Creates The First Tissue-Specific Gene Deletion In Rats

Public release date: 28-Mar-2012 [ | E-mail | Share ]

Contact: Vicki Cohn vcohn@liebertpub.com 914-740-2100 x2156 Mary Ann Liebert, Inc./Genetic Engineering News

New Rochelle, NY -- A novel method for printing human cells onto surfaces in defined patterns can help advance research on tissue engineering and regeneration, as described in an article in Tissue Engineering, Part C, Methods, a peer-reviewed journal from Mary Ann Liebert, Inc (http://www.liebertpub.com). The article is available free online at the Tissue Engineering website (http://www.liebertpub.com/ten).

"Cell printing is one of the breakthrough technologies that will make the application of stem cells for tissue engineering feasible," says John Jansen, DDS, PhD, Methods Co-Editor-in-Chief and Professor and Chairman, Department of Biomaterials, Radboud University Nijmegen Medical Center, The Netherlands.

Yu Fang and colleagues, University of Michigan, Ann Arbor, combined two microscale techniques to dispense and position cells in a variety of patterns. They then demonstrated the ability to use these 3-dimensional cell systems to monitor cell signaling events known to have a role in the growth, proliferation, and metastasis of cancer cells. The authors describe the use of sound waves to deliver microdroplets of cells and polymer-based phase separation to control cell placement in the article "Rapid Generation of Multiplexed Cell Co-Cultures Using Acoustic Droplet Ejection Followed by Aqueous Two-phase Exclusion Patterning." (http://online.liebertpub.com/doi/abs/10.1089/ten.TEC.2011.0709)

###

About the Journal

Tissue Engineering (http://www.liebertpub.com/ten) is an authoritative peer-reviewed journal published monthly in print and online in three parts: Part A--the flagship journal; Part BReviews; and Part CMethods. Led by Co-Editors-In-Chief Antonios Mikos, PhD, Louis Calder Professor at Rice University, Houston, TX, and Peter C. Johnson, MD, Vice President, Research and Development, Avery Dennison Medical Solutions of Chicago, IL and President and CEO, Scintellix, LLC, Raleigh, NC, the Journal brings together scientific and medical experts in the fields of biomedical engineering, material science, molecular and cellular biology, and genetic engineering. Tissue Engineering is the official journal of the Tissue Engineering & Regenerative Medicine International Society (TERMIS). Complete tables of content and a sample issue may be viewed online at the Tissue Engineering website (http://www.liebertpub.com/ten).

About the Company

Mary Ann Liebert, Inc.(http://www.liebertpub.com), is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including Stem Cells and Development, Human Gene Therapy and HGT Methods, and Biopreservation and Biobanking. Its biotechnology trade magazine, Genetic Engineering & Biotechnology News (GEN), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 70 journals, books, and newsmagazines is available at Mary Ann Liebert Inc. (http://www.liebertpub.com).

Go here to see the original:
Innovative cell printing technologies hold promise for tissue engineering R&D

- Human genome and mouse studies identify new precise genetic links

Newswise Working with genetically engineered mice and the genomes of thousands of people with schizophrenia, researchers at Johns Hopkins say they now better understand how both nature and nurture can affect ones risks for schizophrenia and abnormal brain development in general.

The researchers reported in the March 2 issue of Cell that defects in a schizophrenia-risk genes and environmental stress right after birth together can lead to abnormal brain development and raise the likelihood of developing schizophrenia by nearly one and half times.

Our study suggests that if people have a single genetic risk factor alone or a traumatic environment in very early childhood alone, they may not develop mental disorders like schizophrenia, says Guo-li Ming, M.D., Ph.D., professor of neurology and member of the Institute for Cell Engineering at the Johns Hopkins University School of Medicine. But the findings also suggest that someone who carries the genetic risk factor and experiences certain kinds of stress early in life may be more likely to develop the disease.

Pinpointing the cause or causes of schizophrenia has been notoriously difficult, owing to the likely interplay of multiple genes and environmental triggers, Ming says. Searching for clues at the molecular level, the Johns Hopkins team focused on the interaction of two factors long implicated in the disease: Disrupted-in-Schizophrenia 1 (DISC1) protein, which is important for brain development, and GABA, a brain chemical needed for normal brain function.

To find how these factors impact brain development and disease susceptibility, the researchers first engineered mice to have reduced levels of DISC1 protein in one type of neuron in the hippocampus, a region of the brain involved in learning, memory and mood regulation. Through a microscope, they saw that newborn mouse brain cells with reduced levels of DISC1 protein had similar sized and shaped neurons as those from mice with normal levels of DISC1 protein. To change the function of the chemical messenger GABA, the researchers engineered the same neurons in mice to have more effective GABA. Those brain cells looked much different than normal neurons, with longer appendages or projections. Newborn mice engineered with both the more effective GABA and reduced levels of DISC1 showed the longest projections, suggesting, Ming said, that defects in both DISC1 and GABA together could change the physiology of developing neurons for the worse.

Meanwhile, other researchers at University of Calgary and at the National Institute of Physiological Sciences in Japan had shown in newborn mice that changes in environment and routine stress can impede GABA from working properly during development. In the next set of experiments, the investigators paired reducing DISC1 levels and stress in mice to see if it could also lead to developmental defects. To stress the mice, the team separated newborns from their mothers for three hours a day for ten days, then examined neurons from the stressed newborns and saw no differences in their size, shape and organization compared with unstressed mice. But when they similarly stressed newborn mice with reduced DISC1 levels, the neurons they saw were larger, more disorganized and had more projections than the unstressed mouse neurons. The projections, in fact, went to the wrong places in the brain.

Next, to see if their results in mice correlated to suspected human schizophrenia risk factors, the researchers compared the genetic sequences of 2,961 schizophrenia patients and healthy people from Scotland, Germany and the United States. Specifically, they determined if specific variations of DNA letters found in two genes, DISC1 and a gene for another protein, NKCC1, which controls the effect of GABA, were more likely to be found in schizophrenia patients than in healthy individuals. They paired 36 DNA letter changes in DISC1 and two DNA letter variations in NKCC1 one DNA letter change per gene in all possible combinations. Results showed that if a persons genome contained one specific combination of single DNA letter changes, then that person is 1.4 times more likely than people without these DNA changes to develop schizophrenia. Having these single DNA letter changes in either one of these genes alone did not increase risk.

Now that we have identified the precise genetic risks, we can rationally search for drugs that correct these defects, says Hongjun Song, Ph.D., co-author, professor of neurology and director of the Stem Cell Program at the Institute for Cell Engineering.

Other authors of the paper from Johns Hopkins are Ju Young Kim, Cindy Y. Liu, Fengyu Zhang, Xin Duan, Zhexing Wen, Juan Song, Kimberly Christian and Daniel R. Weinberger. Emer Feighery, Bai Lu and Joseph H. Callicott from the National Institute of Mental Health, Dan Rujescu of Ludwig-Maximilians-University, and David St Clair of the University of Aberdeen Royal Cornhill Hospital are additional authors.

See more here:
Genetic Risk and Stressful Early Infancy Join to Increase Risk for Schizophrenia

Public release date: 15-Feb-2012
[ | E-mail | Share ]

Contact: Cathia Falvey
cfalvey@liebertpub.com
914-740-2100
Mary Ann Liebert, Inc./Genetic Engineering News

New Rochelle, NY, February 15, 2012?Therapeutic cancer vaccines, which stimulate the body's immune system to target and destroy cancer cells, are being used in combination with conventional chemotherapy with growing success, as described in several illuminating articles in Cancer Biotherapy and Radiopharmaceuticals, a peer-reviewed journal from Mary Ann Liebert, Inc. (http://www.liebertpub.com). These articles are available free online at http://www.liebertpub.com/cbr

The U.S. FDA recently approved the first cancer therapeutic vaccine for treatment of metastatic prostate cancer. At least 14 other cancer vaccine strategies are in Phase II or III clinical trials for metastatic melanoma, lung cancer, and lymphoma, for example.

A critical perspective, "Recent Advances in Therapeutic Cancer Vaccines," (http://online.liebertpub.com/doi/full/10.1089/cbr.2012.1200) published in the Journal by Jeffrey Schlom, PhD, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD explains that a key advantage of cancer vaccines used in combination with chemotherapy is the extremely low level of toxicity. "The next frontier for vaccine therapy will be the use of vaccines in combination with certain chemotherapeutic agents, radiation, hormone therapy, and certain small molecule targeted therapies," according to Dr. Schlom.

These emerging areas of cancer vaccine therapy are explored in detail in two accompanying research reports by Dr. Schlom's colleagues at NCI/NIH. James Hodge, Hadley Sharp, and Sofia Gameiro describe how a tumor-targeted vaccine can enhance the effectiveness of radiation therapy on cancer growth and spread beyond the primary tumor in the article "Abscopal Regression of Antigen Disparate Tumors by Antigen Cascade After Systemic Tumor Vaccination in Combination with Local Tumor Radiation." (http://online.liebertpub.com/doi/abs/10.1089/cbr.2012.1202) Drs. Hodge and Gameiro and coauthor Jorge Caballero present the molecular signatures of lung tumor cells that can be made more susceptible to immunotherapy when first exposed to chemotherapeutic agents in the article "Defining the Molecular Signature of Chemotherapy-Mediated Lung Tumor Phenotype Modulation and Increased Susceptibility to T-cell Killing." (http://online.liebertpub.com/doi/abs/10.1089/cbr.2012.1203)

"This perspective and promising research reports are from one of the leading vaccine research laboratories in the world," says Co-Editor-in-Chief Donald J. Buchsbaum, PhD, Division of Radiation Biology, Department of Radiation Oncology, University of Alabama at Birmingham. "The ultimate use of cancer vaccines in combination with other immunotherapies, chemotherapy, or radiation therapy will be based on preclinical investigations and hopefully will produce clinical survival benefit for a range of cancers."

###

Cancer Biotherapy and Radiopharmaceuticals, published 10 times a year in print and online, is under the editorial leadership of Editors Donald J. Buchsbaum, PhD and Robert K. Oldham, MD, Lower Keys Cancer Center, Key West, FL. Cancer Biotherapy and Radiopharmaceuticals is the only journal with a specific focus on cancer biotherapy, including monoclonal antibodies, cytokine therapy, cancer gene therapy, cell-based therapies, and other forms of immunotherapy. The Journal includes extensive reporting on advancements in radioimmunotherapy and the use of radiopharmaceuticals and radiolabeled peptides for the development of new cancer treatments. Topics include antibody drug conjugates, fusion toxins and immunotoxins, nanoparticle therapy, vascular therapy, and inhibitors of proliferation signaling pathways. Complete tables of content and a sample issue may be viewed online at http://www.liebertpub.com/cbr

Mary Ann Liebert, Inc. is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including Journal of Interferon & Cytokine Research; Human Gene Therapy and Human Gene Therapy Methods; and Stem Cells and Development. Its biotechnology trade magazine, Genetic Engineering & Biotechnology News (GEN), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 70 journals, books, and newsmagazines is available at http://www.liebertpub.com

Mary Ann Liebert, Inc.
140 Huguenot St., New Rochelle, NY 10801-5215
http://www.liebertpub.com
Phone: 914-740-2100
800M-LIEBERT
Fax: 914-740-2101

[ | E-mail | Share ]

AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.

Follow this link:
Promising early results with therapeutic cancer vaccines

26-10-2011 07:18 Genetic engineering may be one of the greatest breakthroughs in recent history, however, with scientific advancements new ethical issues are raised, forcing us to ask not how, but if we should push genetic research to its absolute limit. This programme looks at the possible benefits of genetic engineering, such as the curing of hereditary diseases and the creation of better, more efficient crops. It also explores the potential issues that arise with this new technology - the questionable morality of cloning, and the controversy that surrounds stem-cell research are two topics which are also investigated.

Link:
Genetic Engineering (excerpt) - Video